The invention relates to a video distributing apparatus for accepting a request of a viewer and automatically forming a distribution schedule of a video image. More particularly, in a transmission medium of multichannels of a satellite broadcasting, CATV, or the like, the invention relates to a video distributing apparatus suitable for use in a video distributing system in which a part of the transmission medium is opened as a request channel for video distribution and is used.
Hitherto, video images have been distributed by a ground wave television broadcasting. The number of channels of the ground wave television broadcasting in one district is up to about ten. A broadcasting station broadcasts a video image as a program and the viewer passively receives it. Home-use video tape or cassette recorders started to spread from about 20 years ago and the viewer can postpone a video view time by recording a television broadcasting. Sales or rental of video tapes also enable a desired video title to be selected. The cable television (CATV) which appeared in the Japanese market about 10 years ago increased the number of channels of the television to tens of channels. Owing to the satellite broadcasting which appeared in recent years, about 100 channels can be viewed at general homes. In future, digitalization of the ground wave television broadcasting is also planned and the realization of multichannels is progressing more and more.
On the other hand, in association with the progress in a transmitting technique and a compressing technique of digital data, study and development have been being progressed in recent years with respect to interactive video presenting services called a video-on-demand (VOD). Attention is paid to the VOD as means that is substituted for the rental video or CATV or as a video viewing method in a computer network. The VOD is a service which enables each viewer to immediately see his desired video title at desired time. The viewer can view a video image selected from a video database by operating it with a feeling using a video tape recorder. However, high costs are required for the VOD because a very high speed network is necessary. As a solution which can be realized in terms of the costs, a service called a near-VOD (NVOD) is considered. According to the NVOD, the same title is repetitively broadcasted by a plurality of channels and start time is shifted little by little (for example, every 15 minutes) for each channel, thereby enabling a video image to be viewed at a relatively free time.
As mentioned above, the VOD is not practical at present because of high costs. The NVOD as a solving measure is still uneconomical since one video title occupies a plurality of channels. The viewer is not free to select a desired title. A method of giving a right of the title option to the viewer has been disclosed in, for example, JP-A-9-247643, JP-A-9-205636, or the like. Even those prior arts, however, have a drawback such that the adaptability, smoothness, and response speed of services are inadequate because the transmitting station side possesses the other right of choice and right of decision.
It is an object of the invention to make it possible to realize a service such that a title which the viewer wants to see can be viewed at desired time and in a desired channel without needing high costs similar to those of the VOD.
To accomplish the above object, according to the invention, there is provided a video distributing system comprising: a video distributing apparatus constructed so as to accumulate and output video data; distributing means for distributing video data outputted from the video distributing apparatus to the viewer; a receiving apparatus for receiving the distributed video data and displaying a video image; and a terminal apparatus which is used to request for the video distributing apparatus to distribute the video image. The video distributing apparatus comprises: memory means in which video data has been accumulated; a schedule table to hold a distribution schedule of the video data accumulated in the memory means; scheduling means for accepting a reservation request from the viewer and updating the distribution schedule registered in the schedule table on the basis of the reservation request; and control means for controlling a distribution of the video data accumulated in the memory means on the basis of the distribution schedule held in the schedule table.
According to a preferred embodiment of the invention, the scheduling means comprises: checking means for discriminating whether the reservation request that is sent from the terminal apparatus can be accepted or not by considering to the distribution schedule of the video data registered in the schedule table; and means for, when it is determined as a result of the check in the checking means that the reservation request can be accepted, registering the reservation data based on the reservation request into the schedule table. The reservation request includes a title of the video data in which the distribution is reserved, a channel which is used to distribute the video data of such a title, and information to designate the start time of the distribution. The checking means discriminates whether the distribution of another video data which is distributed by using the same channel has been scheduled in a time zone that is determined on the basis of the distribution start time which is designated by the reservation request and that is overlapped to a distribution time zone of the video data to be distributed or not and determines whether the reservation request can be accepted or not in accordance with a result of such a discrimination.